Deployment Worksheet

Sep 12, 2014

On the following
worksheet, you can calculate the number of appliances needed for your
installation and the recommended mask field size. The recommended mask size is
1-2 bits larger than the minimum mask size for your installation.

Parameter

Value

Notes

Appliance
Model Used

—

Supported
XenApp and XenDesktop Users Per Appliance

Uspec =

From data
sheet

XenApp
and XenDesktop Users on WAN Link

Uwan =

—

User
overload Factor

Uoverload
= Uwan/Uspec =

—

Supported
BW Per Appliance

BWspec =

From data
sheet

WAN Link
BW

BWwan =

—

BW
Overload Factor

BWoverload = BWwan/BWspec =

—

Number of
appliances required

N =
max(Uoverload, BWoverload) +1 =

Includes
one spare

—

Min
number of buckets

Bmin = N,
rounded up a power of 2 =

—

If
CloudBridge 4000 or 5000,

Bmin =
2*N, rounded up to a power of 2 =

—

Recommended value

B = 4 *
Bmin if Bmin <= 16, else 2 * Bmin =

—

Number of
"one" bits in address mask

M =
log2(B)

If B=16,
M=4.

Mask value: The mask
value is a 32-bit address mask with a number of “one” bits equal to M in the
above worksheet. Often these bits can be the least-significant bits in the WAN
subnet mask used by your remote sites. If the masks at your remote sites vary,
use the median mask. (Example: With /24 subnets, the least significant bits of
the subnet are 0x00 00 nn 00. The number of bits to set to one is log2(mask
size): if mask size is 16, set four bits to one. So with a mask size of 16 and
a /24 subnet, set the mask value to 0x00 00 0f 00.): ______

The above guidelines
work only if the selected subnet field is evenly distributed in your traffic,
that is, that each address bit selected by the mask is a one for half the
remote hosts, and a zero for the other half. Otherwise, load-balancing is
impaired. This even distribution might be true for only a small number of bits
in the network field (perhaps only two or three bits). If this is the case with
your network, instead of masking bits in the offending area of the subnet
field, displace those bits to a portion of the host address field that has the
50/50 property. For example, if only three subnet bits in a /24 subnet have the
50/50 property, and you are using four mask bits, a mask of 0x00 00 07 10
avoids the offending bit at 0x00 00 0800 and displaces it to 0x00 00 00 10, a
portion of the address field that is likely to have the 50/50 property if your
remote subnets generally use at least 32 IP addresses each.

Parameter

Value

Notes

Final
Mask Value

—

Accelerated Bridge

Usually apA

WAN
Service Group

A
service group not already in use on your router (51-255)

LAN
Service Group

Another unused service group

Router IP address

IP
address of router interface on port facing the appliance

WCCP
Protocol (usually "Auto")

—

DC
Algorithm

Use
"Deterministic" if you have only two appliances or are using dynamic load
balancing like HSRP or GSLB. Otherwise, use "Least Disruptive."